1. Field of the Invention
This invention disclosed broadly relates to the field of image processing and more specifically to image processing in a digital camera for taking, storing and displaying panoramic pictures.
2. Description of the Related Art
Today, panoramic photography is accomplished in various ways. One is to use a still camera mounted on a tripod to take a succession of shots as the camera is pivoted around the tripod. In some cameras, a wider than usual strip of film is exposed with special movable optics.
In other cameras, conventional format film, such as 35 mm film, is masked during the exposure in the camera to provide a panoramic effect. The effect is panoramic but the whole exposure is limited by the field of view through the lens.
Other techniques for creating panoramic photography include physically cutting and pasting together strips of exposed film by carefully aligning boundaries between edges of film.
The benefits of electronic photography have led to the growth of digital cameras, which, unlike their film-based counterparts, store images captured in memory into digital memory such as flash memory. To provide panoramic photography effects, these digital cameras can interface with personal computers for joining together two or more images into one image to provide a panoramic effect by joining edge boundaries of images. One such system is disclosed in U.S. Pat. No. 6,682,197, by named inventors Omid A. Moughadam, Stuart R. Ring, and John R. Squilla, entitled “Electronic Panoramic Camera For Use With An External Processor.”
Complicated panoramic digital cameras are available that rely on position sensors or satellite communications for determining position coordinates. These position coordinates are used to help combine the panoramic images. The process of combining scenes taken from different camera orientations is known as “Image Stitching.” One such system is disclosed in U.S. Pat. No. 5,262,867 by named inventor Kiyonobu Kojima entitled “Electronic Camera and Device for Panoramic Imaging and Object Searching” issued on Nov. 16, 1993.
A panoramic camera with a memory device for storing data from a previously photographed portion of an object and a control device for enabling the display device to substantially display both the image to be photographed and the image already photographed and stored in the memory space is described in U.S. Pat. No. 5,138,460 by named inventors Egawa and Akira entitled “Apparatus for forming Composite Images” issued on Aug. 11, 1992.
Other techniques for stitching two or more still images together are disclosed in the patent application Ser. No. 09/477,036 now issued as U.S. Pat. No. 6,677,981, entitled “Motion Play-Back of Still Picture Comprising A Panoramic View for Simulating Perspective” with inventors Massimo Mancuso et al, filed on Dec. 31, 1999, and commonly assigned herewith to STMicroelectronics, Inc. and hereby incorporated here into in its entirety. Each of the still images forming the panoramic image in this application is stored separately and the panoramic scene is reconstructed or stitched together each time it is needed. More specifically, the panorama image is built strip-by-strip as pictures are captured, each strip is stored individually, and the panoramic is built strip by strip as still images are captured. The panoramic scene is obtained by abutting the successive strips.
Although the prior art techniques described above are useful for panoramic capture techniques, these prior art techniques are not without their shortcomings. One shortcoming with the techniques above, is that additional memory is required to save the panoramic image separately from the original images composing the panorama. Accordingly, a need exists for a method and system to store images that requires minimum memory size to store the panoramic image or to provide the panoramic functionality without actually storing the panoramic image.
Another shortcoming is how the panoramic image is stored. Specifically, the prior art systems store the panoramic image in strips or in a format other than the complete panoramic image. A panoramic image format that is stored in strips or in a format other than the complete image is useful only for a stitching application. Other applications, such as, an electronic photo album, process each strip as a single image and displays each image separately. This displaying of each strip separately many times confuse the user since the entire panoramic is not displayed at once. Accordingly, a need exists for a method and a system to store still images in an image format that is compatible with other image formats such as JPEG.
Another shortcoming with the techniques above, is that pictures saved with original parameters such as motion estimation, color correction, focal length and other image stitching parameter are not compatible with popular storage formats such as JPEG (Joint Photographic Experts Group ISO standard 10918). In fact, along with the Graphic Interchange Format (GIF) file, the JPEG is a file type supported by the World Wide Web protocol. Accordingly, needs exists for a method and apparatus to store images with panoramic parameters in such a way that the image storage format is compatible with other still image formats such as JPEG.
Another shortcoming with the techniques above is that the user is left with very little choice for correcting imperfections in the panoramic image after it is captured if the parameters of motion estimation and color correction are lost. Accordingly, a need exists for a method and a system to reconstruct and stitched together still images forming a panoramic scene with more user control for correcting imperfections such as motion estimation and color correction.